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          <div class="quiz-container">
            <div class="quiz-header">
              <h1>kafka中消费者组 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
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      <script>
        const quizData = [
  {
    "question": "在 Kafka 消费者组中，被称为“协调器 (Coordinator)”的组件，其核心职责不包括以下哪一项？",
    "options": [
      "监控消费者实例的加入和离开，并触发再平衡。",
      "负责将消息进行序列化，以便消费者能正确解析。",
      "追踪并管理每个消费者在每个分区上的消费偏移量 (offset)。",
      "根据分配策略，决定将哪些分区分配给哪个消费者实例。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "协调器 (Coordinator) 是消费者组的管理中心，其主要职责包括管理组成员（加入/离开）、负责分区分配与再平衡，以及管理消费偏移量。消息的序列化/反序列化是由生产者和消费者客户端的配置（如 key.deserializer 和 value.deserializer）决定的，不属于协调器的职责范围。",
    "source": "文档中「消费者组的工作原理」->「2. 消费者组协调器」部分",
    "hint": "协调器的三大职责是成员管理、分区分配和偏移量管理。请思考哪个选项超出了这个范围。"
  },
  {
    "question": "根据文档，当一个消费者实例加入或离开消费者组时，会触发一个关键过程，这个过程被称为什么？",
    "options": [
      "偏移量提交 (Offset Commit)",
      "数据同步 (Data Synchronization)",
      "重平衡 (Rebalancing)",
      "故障转移 (Failover)"
    ],
    "correctAnswerIndex": 2,
    "explanation": "消费者组的重平衡 (Rebalancing) 是指当消费者实例数量发生变化（如新成员加入、现有成员离开或宕机）时，协调器触发的分区重新分配过程。这个机制确保了工作负载能够在活跃的消费者之间保持均衡，并实现了容错。",
    "source": "文档中「消费者组的工作原理」->「4. 消费者组的重平衡」部分",
    "hint": "文档中提到，当消费者成员发生变化时，为了重新分配分区以保持负载均衡，会启动一个特定的协调过程。"
  },
  {
    "question": "关于 Kafka 消费者组内分区分配的基本规则，以下哪项描述是正确的？",
    "options": [
      "一个分区可以被同一个消费者组内的多个消费者实例同时消费，以提高效率。",
      "一个消费者实例一次只能订阅并消费一个分区。",
      "一个分区在同一时间只能被同一个消费者组内的一个消费者实例消费。",
      "所有消费者实例共享同一个消费偏移量，以确保数据一致性。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "这是 Kafka 实现并行处理和保证分区内消息顺序性的核心原则。一个分区在同一时刻只能分配给组内的一个消费者。这样既实现了负载均衡（多个分区由多个消费者处理），又保证了单个分区内消息的消费顺序不会被打乱。如果多个消费者能消费同一个分区，顺序性将无法保证。",
    "source": "文档中「消费者组的特性和优势」->「1. 特性和工作原理」->「分组消费」部分",
    "hint": "思考一下 Kafka 是如何通过消费者组既实现并行处理，又保证单个分区内消息顺序性的。"
  },
  {
    "question": "在配置一个新的 Kafka 消费者时，如果将 `auto.offset.reset` 参数设置为 “latest”，并且该消费者组之前从未消费过这个主题，那么消费者的行为会是怎样的？",
    "options": [
      "从分区的最旧（最早）的消息开始消费。",
      "消费者会抛出异常并停止运行。",
      "从消费者启动后到达分区的最新消息开始消费。",
      "等待协调器手动指定一个起始偏移量。"
    ],
    "correctAnswerIndex": 2,
    "explanation": "`auto.offset.reset` 参数定义了在找不到有效消费位移（offset）时消费者的起始位置。'latest' 策略意味着消费者将忽略分区中已经存在的历史消息，只从它启动之后新到达的消息开始消费。与之相对的是 'earliest'，它会从分区的最开始处进行消费。",
    "source": "文档中「消费者组的配置和管理」->「1. 消费者组的配置参数」部分",
    "hint": "这个参数决定了“新来的”消费者从哪里开始读。`latest` 关注的是“未来”，而 `earliest` 关注的是“历史”。"
  },
  {
    "question": "在监控消费者组的性能时，一个关键指标 “消费者 Lag (落后)” 反映了什么情况？",
    "options": [
      "消费者处理单条消息的平均延迟时间。",
      "消费者组当前消费进度落后于分区最新消息的数量。",
      "消费者组中处于非活跃状态的消费者实例数量。",
      "从上次重平衡到现在所经过的时间。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "消费者 Lag（落后）是一个非常重要的监控指标，它表示消费者当前已提交的偏移量与该分区日志末端（即最新消息）的偏移量之间的差值。这个数值可以直观地反映消费者的处理速度是否跟得上消息的生产速度，Lag 过大通常意味着消费积压，需要关注。",
    "source": "文档中「消费者组的监控和调优」->「监控消费者 Lag」部分",
    "hint": "这个指标衡量的是消费的“进度”，如果把消息队列比作一条跑道，它衡量的是消费者距离终点还有多远。"
  },
  {
    "question": "文档中提到了多种消费模式，其中哪种模式下消费者需要“手动指定要消费的分区列表”，通常用于需要精确控制处理顺序或保证强一致性的场景？",
    "options": [
      "独占消费模式 (Exclusive Consumer Mode)",
      "平衡消费模式 (Balanced Consumer Mode)",
      "批量消费模式 (Batch Consumer Mode)",
      "实时消费模式 (Real-time Consumer Mode)"
    ],
    "correctAnswerIndex": 0,
    "explanation": "独占消费模式与默认的平衡消费模式不同，它不依赖协调器进行自动分区分配。在这种模式下，开发者需要明确地为消费者实例分配其要消费的分区。这确保了每个分区严格由一个指定的消费者处理，避免了因重平衡导致的分区交接，适用于订单处理等对顺序性要求极高的场景。",
    "source": "文档中「消费者组的消费模式」->「2. 独占消费模式（Exclusive Consumer Mode）」部分",
    "hint": "与自动“平衡”分配相对的是哪种模式？这种模式给予了开发者更多的控制权。"
  },
  {
    "question": "Kafka 消费者组通过哪项核心机制，来确保当某个消费者实例宕机时，其负责处理的消息能被其他健康的消费者接管，从而实现容错和高可用性？",
    "options": [
      "ISR (In-Sync Replicas) 机制",
      "分区分配和重平衡机制",
      "手动提交消费位移",
      "批量消费模式"
    ],
    "correctAnswerIndex": 1,
    "explanation": "消费者组的容错能力主要依赖于其分区分配和重平衡机制。当协调器检测到某个消费者实例失效（通过心跳机制），它会触发一次重平衡，将原本分配给失效实例的分区重新分配给组内其他存活的消费者。这样就确保了消息处理不会中断，保证了系统的高可用性。ISR是保证Broker层面数据可用性的机制，与消费者容错不同。",
    "source": "文档中「消费者组的作用」->「4. 容错和高可用性」->「故障转移」部分",
    "hint": "思考一下，当一个“工人”突然离开，系统是如何把他的任务自动分配给其他“工人”的？"
  }
];
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          optionsListEl.innerHTML = '';
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            nextBtn.style.display = 'block';
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            nextBtn.disabled = false; // 最后一题时，下一题按钮不禁用，而是用于显示报告
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                hintContainerEl.textContent = ''; // 清除旧的提示内容
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            const resultBox = document.createElement('div');
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            html += `<div class="source-text">来源: ${questionData.source}</div>`;
            
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            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

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                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  